Many folks have (or develop) sensitivity to molds and chemicals that are immediately noticeable. Other times it takes longer as we age and our immune systems start to decline. Everyone is different. But when one room in your home gives you such immediate discomfort there almost always a hidden microorganism to blame. Better bring in a mold specialist.
Actively growing molds have a distinctive musty aroma associated with their life cycle. Picture walking into a basement and what aroma is typically associated with that environment. If you smell smoke, there’s almost always a fire. A pro would help you determine what is going on with that aroma.
It’s not unusual to have become so de-sensitized to the aromas associated with your home after living there for decades. Many times folks new to your home will notice the unusual aroma and mention it to you. You should hire a professional and investigate this further as things are not as they always seem to you.